From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794332247; b=UbuF94DvlsI2nWFeEiePcvHckpVfIBopjW0tZKQ2C7T3fonrEr0nLfT3jGoS3dlWZbdu PBXAbyrTUt3B8TDx57G1hRBUlNg6M+Gqqr63l2LJjOWIKEEmLmK7KO3GkBsuMN0iJvlnA THXwJVNIqpaz0BoLld9xYkxpEFhXsVPRTtOmp+KByTDim3aAWsjDu+bRBELZBjvOBeptz +5zDNEMbCrIH4GzuBPriXLn+hqx12tnkR45NnKyXYb/4Ys+vIk1VqXFzl7quJOTz7Z/a2 urSKS+1lzY/+Qpu3ZEr2S7Qv0kYlITJLUcgxzJXz1XRWdRe78j6mbooGpeKVHog3djA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794332247; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=I9F5kTMVg6XTR6qfdDMXgSzforUB18H9jRqALhWbfu0=; b=Sw1ShNP+AT4sJW+LLemRfMAPZAjPDN14aXkdLOhKakFYgLpRn6V3hF2FyfREy0Q2fYhT u8ZQh1bMIBhfsa1ggUazSvV/CwiHPckoxJMExIT1N0C7BbQFaIK5QPwsjGACkt2U/g6+T GOMDVa9H2P446R+GvV4jM/g+DjuN5ZdS9cC5IErz9iXt5rN/zAKvIjgF+MXeB70/sOJYU t670XqPoofzRv6u5G0QB6m7OuDzOSEZPX/ZUTXG6LF1DSikV3ZHmQPphc2tDceQgyQ+Jq l6A2DOCblo3e0Q1PjAq3NRs1AFHXLJOQ+7jqfvOt7qMT4qkQjDCvvYX9R4aq6M0PNRw== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b="Db/nCmOi"; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F3DFB606A320 for ; Tue, 10 Nov 2026 17:37:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=Db/nCmOi Received: by smtp.kernel.org (Postfix) with ESMTPSA id B36721F008A2; Tue, 10 Nov 2026 17:37:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794332246; bh=I9F5kTMVg6XTR6qfdDMXgSzforUB18H9jRqALhWbfu0=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Db/nCmOiZwCm341hlRIIIc2qOK9nsbX3sUO6CEnyzEER4UdXu40cTPHHyEewYwX9T g+xIkHxkpMORdbvdlGJh/CvoPmxIr6LGVYVIDyjPJpSfZBJ399K+amO6Z0O1c8O4U0 Koa8+sbDNMNenpbTpBU/3fg+YKQSR+3SWOHD73bmiEJyNPJ18IWqY2gh7EWUSavsnJ qv3dkRrfgE8pj1GICwCpllIfD3uXhPwTkVRIyL2TArNIbN8Z9Az8fGYwoE1cQ/GRu3 rMwxyNxwj33JZOta/cXe6ropqc6IGR1Ba45OCSigeMiXy1MawWGMVbqqgZo+2Lz8C0 421g3dVC9LnPg== From: Sasha Levin To: stable@vger.kernel.org Cc: Nanzhe Zhao , Chao Yu , Barry Song , Jaegeuk Kim , Sasha Levin Subject: [PATCH 5.15.y] f2fs: remove mappedtodisk flag usage in mmap write path Date: Tue, 10 Nov 2026 12:37:23 -0500 Message-ID: <20261110173704.2986892-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261107060537-failed-5.15-b3c984358925@kernel.org> References: <20261107060537-failed-5.15-b3c984358925@kernel.org> X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Nanzhe Zhao [ Upstream commit b3c9843589257631bac18f30655e82d88970688a ] PG_mappedtodisk was inherited from the nobh/buffer-head era. However, f2fs has no buffer heads and the flag is no longer meaningful. The only user of the flag is the "no holes" shortcut in f2fs_vm_page_mkwrite(), which makes mmap write faults skip marking the folio dirty. Moreover, it causes the following race condition with filesystem freezing: CPU0 (write fault) CPU1 (freeze_super) ---- ---- f2fs_vm_page_mkwrite() sb_start_pagefault() /* shortcut: no dirty */ sb_end_pagefault() sb_wait_write(SB_FREEZE_PAGEFAULT) /* no waiter, passes */ sync_filesystem() /* folio not dirty, skipped */ finish_fault() /* PTE writable */ fault_dirty_shared_page() folio_mark_dirty() /* dirty folio on a frozen fs */ It will also skip APP_MAPPED_IO iostat/REQ_TIME updates and post-EOF folio zeroing. Remove this shortcut in f2fs_vm_page_mkwrite() and stop setting it in f2fs_read_single_page(). Reported-by: Chao Yu Link: https://lore.kernel.org/linux-f2fs-devel/496b913c-eb81-4fa8-be72-c6a06a10aba2@kernel.org/ Reviewed-by: Chao Yu Reviewed-by: Barry Song Fixes: fbfa2cc58d53 ("f2fs: add file operations") Cc: stable@vger.kernel.org Signed-off-by: Nanzhe Zhao Signed-off-by: Jaegeuk Kim [ sashal: adapted folio flag removals to the page-based SetPageMappedToDisk() and PageMappedToDisk() APIs ] Signed-off-by: Sasha Levin --- fs/f2fs/data.c | 1 - fs/f2fs/file.c | 6 ------ 2 files changed, 7 deletions(-) diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c index 90cb8560af1d0..eceb3179173d0 100644 --- a/fs/f2fs/data.c +++ b/fs/f2fs/data.c @@ -2163,7 +2163,6 @@ static int f2fs_read_single_page(struct inode *inode, struct page *page, got_it: if ((map->m_flags & F2FS_MAP_MAPPED)) { block_nr = map->m_pblk + block_in_file - map->m_lblk; - SetPageMappedToDisk(page); if (!PageUptodate(page) && (!PageSwapCache(page) && !cleancache_get_page(page))) { diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c index 892f19f67904f..dd4eab6367a66 100644 --- a/fs/f2fs/file.c +++ b/fs/f2fs/file.c @@ -135,12 +135,6 @@ static vm_fault_t f2fs_vm_page_mkwrite(struct vm_fault *vmf) /* wait for GCed page writeback via META_MAPPING */ f2fs_wait_on_block_writeback(inode, dn.data_blkaddr); - /* - * check to see if the page is mapped already (no holes) - */ - if (PageMappedToDisk(page)) - goto out_sem; - /* page is wholly or partially inside EOF */ if (((loff_t)(page->index + 1) << PAGE_SHIFT) > i_size_read(inode)) { -- 2.53.0